In recent years, for the purpose of energy saving, weight reduction and the like, flat-panel displays using liquid crystals, plasma or the like have become popular. For these display-related materials, many functional films having optical properties are used. Since these materials are easily deteriorated by UV rays, in order to improve the resistance to light, there are increased demands for an UV-absorbing agent having excellent absorbing capacity in a variety of wavelength regions.
As such UV-absorbing agent, triazine compounds such as 2-(2-hydroxyaryl)-4,6-diaryl-1,3,5-triazine, 2,4-bis(2-hydroxyaryl)-6-aryl-1,3,5-triazine, 2,4,6-tris(2-hydroxyaryl)-1,3,5-triazine and 2,4,6-tris(2,4-dihydroxyaryl)-1,3,5-triazine are known. Particularly, since 2,4,6-tris(2-hydroxyaryl)-1,3,5-triazine and 2,4,6-tris(2,4-dihydroxyaryl)-1,3,5-triazine function as UV-absorbing agent having excellent UV-absorbing capacity in a long-wavelength region, these triazine compounds are expected to be used in an application such as polarizing plate protecting film, where absorbing capacity in a long-wavelength region is required.
In view of this, for the purpose of providing such triazine compound, Patent Documents 1 to 7 disclose methods of producing such triazine compound. For example, Patent Document 1 discloses a production method in which aluminum chloride is used as Lewis acid, and Patent Document 2 discloses a production method in which benzene is used as the solvent.